The progress made on this project during the past year has resulted in the development of three methods for determining polyaromatic drugs at nanogram concentrations in small amounts of serum. Diazepam and its active metabolite nordiazepam have been assay by both liquid chromatography utilizing ultraviolet detection and gas chromatography utilizing electron-capture detection. Significant clinical data on the concentrations of the two drugs in the serum of patients at steady-state has been obtained. The correlation of serum and urine concentrations of the two drugs in the same patients has been established. A liquid chromatographic method for determining unmetabolized morphine in small serum specimens using electrochemical detection has been developed. The procedure can quantitatively assay as little as one nanogram/ml providing a two ml specimen is utilized. A monitoring of morphine serum concentrations after 5 and 10 mg doses of morphine in the epidural cavity has been accomplished with concentrations generaaly on the lower side of the accepted therapeutic range. In addition, a procedure for assaying many of the phenothiazine compounds at therapeutic concentrations in serum has also been developed. Data correlating promethazine concentrations in serum after both oral and rectal doses has been obtained.